Question

How can be the molecular geometry of a compound determined\[?\]

Answer 1

Hint:Try to apply VSEPR theory $($Valence shell electron pair repulsion theory$)$ in this question. Using the VSEPR theory, we can determine the number of bond pairs and lone pairs of electrons that are present on the central atom of the given compound and from there try to predict the geometry of the compound.

Complete step-by-step answer:The VSEPR theory $($Valence shell electron pair repulsion theory$)$ is basically a model used to determine the geometry of a molecule from the number of electron pairs surrounding the central atom of the molecule.
According to VSEPR theory, for a given molecule the central atom has to be chosen first and the total number of valence electrons must be counted and from the electron count of the central atom the structure of the molecule is predicted.
Now, if the total electron count of the central atom of a molecule is $4$ then the structure of the molecule is linear.
If the total electron count of the central atom of a molecule is $6$ then the structure of the molecule is planar trigonal.
If the total electron count of the central atom of a molecule is $8$ then the structure of the molecule is tetrahedral.
If the total electron count of the central atom of a molecule is $10$ then the structure of the molecule is trigonal bipyramidal.
If the total electron count of the central atom of a molecule is $12$ then the structure of the molecule is octahedral.
If the total electron count of the central atom of a molecule is $14$ then the structure of the molecule is pentagonal bipyramidal.
In this way by determining the total electron count of the central atom you can determine the geometry of a molecule.

Note:The most important part in this kind of question is to know the valence shell electron count of the central atom and the contribution of the neighbouring atoms to the electron count of the central atom. If the electron count is correct you can determine the geometry of the compound easily.